RTX2R4WS
Students participate in a fine arts exam in Wuhan, Hebei Province, China, Oct. 30, 2016. Reuters

A large crowd at a school toilet block in Puyang, China, turned deadly Wednesday when a stampede broke out. The incident at Number Three Experimental Primary School resulted in the death of two students and the injuries of 20 others, according to local news reports.

The primary school students began piling into a toilet during a morning break after a morning exam. The toilet's wall collapsed, leading to a panicked stampede, according to a parent's social media post referenced in the South China Morning Post.

Injured students, some of which were reported to be in serious condition, were rushed to a hospital as parents crowded around the school for further news. The number of student injuries and casualties were confirmed by local officials. Puyang county's government told the Associated Press the incident was under investigation but wouldn't provide further details.

Read: Mecca Hajj Stampede Death Toll Is 2,411, Three Times Figure Reported By Saudi Government

The is not the first time a stampede in China turned deadly. In 2015, 36 people died during a new year’s event in Shanghai by a riverfront. In 2014, a stampede on a staircase at another school located in South West China resulted in the death of six children and 25 reported injuries.

Researchers that focus on crowd management typically look to how to prevent stampedes from breaking out but further research conducted on why they occur and what happens once a stampede begins are still developing, the Washington Post reported in 2015.

“It’s all about math, management and psychology,” crowd safety and risk analysis specialist G. Keith Still said of mass crowds in a separate interview with the Washington Post.

Understating the science and nature of large crowds is vital to safety. “Crowds are dynamic systems,” Still said. “But they’re made of people.”